Chemical Nomenclature


In the early beginnings of chemistry, the chemical name of a compound and its chemical formula had little or no relationship to each other.  Modern naming methods have corrected this lack of connection between chemical formulas and chemical names.  Mastery of these methods is an important part of communication in the scientific community. This event assesses both the level at which students are capable of communicating using the International Union of Pure and Applied Chemistry (IUPAC) naming rules, as well as their familiarity with the older common names.


  • This event must be completed by a team of 3 students. Each of the three students will work independently on separate tests at the same time.   Once they have completed their test, a raw score will be determined by combining the scores of the three individuals. 
  • During a 25 minute session, students take a computerized test customized for the NJCO will be used in this competition. The exam assesses a student's ability to name and write the formulas for the following types of compounds:
    • ionic compounds containing common ions (ex: AgCl)
    • ionic compounds containing​ polyatomic ions (ex: Nasodium tetraborate)
    • binary molecular compounds (ex: CO2)
    • Acids (ex:  H3PO4)
    • common substances (ex: gypsum, brimstone)
    • organic compounds - including aliphatic, alicyclic and aromatic compounds  (ex: dichlorobenzene)
    • organic compounds containing functional groups (ex: methyl ethanoate) - limited to one type of functional group per compound
    • coordination compounds (ex: tetrachloronitrocobalt (III) chloride)
    • hydrated compounds (ex: Pb(CH3CO2)2 • 3H2O)


  • Two examples of the computerized test are available using the files linked at the bottom of this webpage.  Please note that this file uses Adobe Shockwave.  The password to start the quiz is njco.
  • In many cases, more than one answer is accepted by the program.  Certain notation such as the correct use of parentheses and brackets must be entered correctly.  Therefore, it is imperative that students familiarize themselves with the testing platform we will be using. 
  • The exam uses the Adobe Shockwave plug-in
Practice Exam #1
Practice Exam #2



  • The exam on Event Day will present the questions in a random format and the answers will not be shown.
  • Students may not fast-foward/skip question, nor may they return to a test question after an unsuccessful attempt.  The correct answers to the questions will not be provided the day of the event.
  • The time each student takes to complete the exam is recorded for tie-breaker purposes only.



  • Teams earn up to 2 points for each answer (between 0.2 - 2.0 points) for a total individual score of 100 points. The time taken to complete the test will also be considered in scoring.  The team’s score for this event will be determined by averaging the three individual scores.  
  • The American version of the rules of nomenclature as established by the International Union of Pure and Applied Chemistry (IUPAC), found in the most recent edition of the CRC Handbook of Chemistry & Physics will be used in guiding judging.